Question

The perimeter of a rectangular pool is 50 m. If the pool is 15 m long, then the width of the pool is:

• A. $12m$
• B. $10m$
• C. $15m$
• D. $5m$

Answer 1

The correct option is B $10m$

The perimeter $P$ of a rectangle is given by the formula, $P=2(l+w)$, where $l$ is the length and $w$ is the width of the rectangle.
Given, length of the rectangular pool $l=15m$ and permieter $P=50m$
$\because P=2(l+w)\Rightarrow 50=2\times (15+w)\Rightarrow 50=2\times 15+2\times w\Rightarrow 50=30+2w$
Subtract 30 from both sides
$\Rightarrow 50-30=30+2w-30$
$\Rightarrow 20=2w$
Divide both sides by $2$
$\Rightarrow \frac{20}{2}=\frac{2w}{2}$
$\Rightarrow 10=w\Rightarrow w=10$

Hence, the width of the pool is $10m$
Option (b.) is the correct choice.